1. Field of the Invention
The present invention relates to an optical disk apparatus for recording information on or reproducing information from an optical disk.
2. Description of the Related Art
Various disk apparatus have been developed which record information on an optical disk and reproduce information from the disk with laser beams emitted from a laser, such as a semiconductor laser.
The access mechanism used with a conventional optical device comprises a linear motor for moving an optical head in a radial direction of an optical disk so as to gain coarse access and an objective lens driving mechanism for moving an objective lens installed in the optical head so as to gain fine access. To gain access to a target track using such an access mechanism, the linear motor is first driven for coarse access. By this coarse access the optical head is moved near to the target track. Subsequently track position information is read by the optical head, which represents the position of a track that the optical head faces. A difference between the read track position information and the target track position information is then calculated. If the difference is small, the objective lens is driven for fine access (tracking), whereas if the difference is great, the linear motor is driven again for coarse access.
The above access mechanism, however, has a long access time due to a combination of coarse access and fine access.